In the past, continuous filament fabrics have been developed to imitate silk in appearance, hand and drape by twisting 40-100 denier continuous multifilament yarn to a level of 40 to 70 TPI, weaving them on conventional fly shuttle looms, and subsequently developing the crepe of the fabric by boiling the fabric in a relaxed state for an extended period of time.
High twist yarn of this type, however, proves difficult to process, in part because of the snags, kinks and general tangling caused by the liveliness of the yarn, particularly as it leaves the supply package. In the past, attempts have been made to stabilize the yarn through additional process steps, such as conditioning the yarn by steaming in the 139.degree.-140.degree. F. range for extended periods of time, e.g., up to four hours. After heat treatment, the yarn may be sized, using conventional sizing materials such as polyvinyl alcohol, polyacrylic acid and carboxyl methyl cellulose, woven and, finally, exposed to scouring and boiling operations. See, for example, U.S. Pat. No. 2,857,653, issued Oct. 28, 1958.
In U.S. Pat. No. 2,772,191, issued Nov. 27, 1956, conventional sizing is applied to twisted yarn to reduce the liveliness of the yarn, followed by knitting and removal of the size.
It is also known to add tension and anti-snag devices on the supply package to prevent kinking and snarling as the twisted yarn is wound onto a quill. During the subsequent weaving operation, it is known to use a shuttle equipped with fur and nylon loops to control kinking of the yarn coming off the quill. There may also be a tension device in the shuttle itself, just before the shuttle eye, to keep the yarn tight as it is being pulled across the shed of the warp.
After weaving, the woven cloth is typically processed through a creeping operation which subjects the fabric in a relaxed state to a gradual rise in temperature, up to between 210.degree. and 250.degree. F. in an aqueous bath. A pressure rotary washer may be required to reach temperatures above 212.degree. F. The developed fabric is subsequently dyed and finished.
With the development of high speed looms such as the water jet and air jet looms, however, and the automation of related operations, the steps usually required to produce a good crepe fabric using high twist yarn have become costly if not almost impossible to carry out. For example, in the prior art as noted hereinabove, the liveliness of the high twist yarn could be controlled through utilization of a tension device in the shuttle just ahead of the shuttle eye to keep the yarn tight as it was being pulled across the shed of the warp. With water or air jet looms, the yarn has to be at very low tension to be carried across the shed with a burst of water or air. To compensate for this reduction in tension control, higher temperatures must be employed during conditioning of the yarn prior to weaving in order to control the liveliness of the yarn. However, the higher temperatures reduce the creping power of high twist yarns. Additional finishing equipment required to overcome part of this lost tendency to develop crepe is costly in terms of both labor and equipment.